Beta cell dysfunction and death is, in part, due to autoimmunity against beta cells, which contributes to the rising blood glucose level in patients with type 1 diabetes (T1D). There is a correlation between autoantibody positivity and loss of beta cell function. However, in order to identify individuals not only at risk but with actual ongoing disease prior to loss of metabolic control, a direct measure of beta cell death is needed. Provided herein are solutions to these and other problems in the art.